What to know about Pfizer and Moderna's COVID-19 vaccine trials

The nation's top infectious disease expert, Dr. Anthony Fauci, says as many as 20 million Americans could get a COVID-19 vaccine by the end of 2020. Dr. Uché Blackstock, an emergency physician and founder of the group Advancing Health Equity, joins CBSN's "Red & Blue" host Elaine Quijano to discuss the encouraging early results from vaccine trials by Moderna and Pfizer.